This project attempts to address the gap between the technological development of Augmentative Communication Devices (ACDs) and our understanding of the cognitive and linguistic processing needed for their use. Towards this goal, I propose to study the influence of ACDs on the way users and their partners communicate. The research is aimed at determining the effects on communication of the type of device used as well as the permanancy, redundancy, and temporal/spatial characteristics of the message created by the device. These device related variables will be studied for their influence on (1) the user's ability to refer to subjects and events; (2) the receiver's ability to comprehend the message; (3) the user's and receiver's ability to manage the interaction, and (4) the judgments receivers and observers make about the competence of the ACD users. Based on the data obtained from these studies, a model of augmentative communication will be developed and evaluated for how well it predicts conversational performance in experimental and naturalistic contexts. Years 1-3 will involve the study of dyadic communication in a controlled experimental context. Nonhandicapped adults will serve as subjects to reduce the subject variability found among handicapped users. Research during years 3 and 4 will extend the experimental work to include single-subject studies of handicapped ACD users in both experimental and naturalistic settings. Finally, a prototype ACD will be developed using the findings of the studies. The overall aim is to develop a set of social communication specifications for the production of a new generation of socially appropriate communication technologies.